1. Field of the Invention
The present invention relates to a plasma addressed electro-optical display having a drive substrate connected to an image display panel thereof through a circuit board, and more particularly to uniform capacitances of adjacent electrodes.
2. Description of Prior Art
A so-called plasma addressed electro-optical liquid crystal panel, such as a liquid crystal panel and a plasma display, must have drive electrodes formed into matrix configuration to correspond to pixels. The drive electrodes are generally disposed over the width of the display panel.
The drive electrodes must be electrically connected with an external drive circuit. Hitherto, the display panel and the drive substrate have been connected to each other through a flexible circuit board.
When a large display panel is manufactured, establishment of the connections to all of the drive electrodes on one flexible circuit board is not a practical idea. Thus, the drive electrodes are sectioned into a plurality of electrode groups which are connected as described above on a plurality of flexible circuit boards.
The coupled capacitances of electrodes of a flexible circuit board will now be considered. Since the distances between electrodes are substantially constant on he same flexible circuit board, the coupled capacitances are substantially the same between the adjacent electrodes.
If a plurality of flexible circuit boards are used to establish the connection as described above, the coupled capacitances of adjacent electrodes are undesirably reduced at the outermost electrodes on the adjacent flexible circuit boards.
The reason for this lies in that the distance between electrodes is elongated between adjacent flexible circuit boards as compared with the distance on the same flexible circuit board.
If the coupled capacitances of the adjacent electrodes are different from each other, the waveform of the voltage which is applied to the drive electrode of the display panel becomes different in only the foregoing portion. It leads an influence of the capacitance difference on the displayed image in the boundary between the flexible circuit boards. In particular, a plasma addressed electro-optical display is considerably affected by the difference. As a result, undesirable lines appear in the image frame.